This six-volume series of Sight Reduction Tables for Marine Navigation is designed to facilitate the practice of celestial navigation at sea by the Marcq Saint Hilaire or intercept method. The tabular data are the solutions of the navigational triangle or which two sides and the included angle are known and it is necessary to find the values of the third side and adjacent angle. The tables, intended for use with The Nautical Almanac, are designed for precise interpolation of altitude for declination by means or interpolation tables which facilitate linear interpolation and provide additional for the effect of second differences when required. The concept, design, development, and preparation of these tables are the results of the collaborative efforts and joint accomplishments of the National and Mapping Agency, the U.S. Naval Observatory, and Her Majesty's Nautical Almanac Office, Royal Greenwich Observatory. The tabular material in identical format has been published in the United Kingdom by the Hydrographic Department, Ministry of Defense (Navy), as N.P. 401. The reprint was complied on a Hewlett Packard K420 server with an HP C180 client workstation, and was composed in its entirety as a digital document.